A number of warning devices have been proposed in the past which have the objective of warning operators of vehicles of unsafe conditions in the path of movement. The following U.S. patents, for example, are relevant to this basic concept:
U.S. Pat. No. 2,116,604, which discloses a means for operating the brakes of a vehicle when inpact is sensed. The means includes a net to catch persons hit by a vehicle and arms to push persons out of the path of vehicle travel.
U.S. Pat. No. 3,407,874, which discloses a flexible member mounted on a solenoid switch, which switch activates an alarm or horn when the flexible member is deflected by contact with a foreign object. Similar systems are shown in U.S. Pat. Nos. 2,588,815 and 2,720,275 which disclose systems having sensors adapted to engage an object into which a backing vehicle comes in contact and thereupon to activate the vehicle brakes and alarm systems.
One major difficulty with existing systems is that they fail to provide visual warning to alert persons of the danger of being behind a backing vehicle. To overcome this difficulty, the present vehicle control device is provided with a sensor having a large surface that displays warning precautions and at the same time is adapted to activiate the brakes and alarm system upon striking or impacting on an object in the path of movement of the vehicle. The vehicle control system of the present invention is adaptable for use on a variety of different sizes and types of vehicles and can be adjusted to determine the size of object which will activate the system.
The known devices do not adequately protect against damage to small objects or injury to small persons in the path of movement of the vehicle provided with them, and, while possibly operable under limited circumstances when the vehicle is traveling on a smooth or uniform surface, do not discriminate between sensor movement caused by surface irregularities and do not provide for manual override of the control circuit to make the system non-operational in situations where operation of brakes is not needed, even though the sensor is actuated.
Furthermore, the known devices are not adaptable to sensing of objects during forward travel of a vehicle and do not sense objects falling from or coming to the side of a vehicle to a position in front of a rear vehicle wheel.